Glass hone plate resurfacing apparatus



I 1957 J. E. P. PICKETT I 3,

GLASS HONE PLATE RESURFACING APPARATUS Filed Feb. 15, 1965 I 2 Sheets-Sheet l INVENTOR. John E. P Pickett zzw ATTORNEY 1967- J. E. F. PICKETT I 3,

GLASS HONE PLATE RESURFACING APPARATUS Filed Feb. 15, 1965 2 Sheets-Sheet 2 FIG. 4 FIG. 7

INVENTOR- John E" P. Pickett ATTORNEY United States Patent 3,349,520 GLASS HONE PLATE RESURFACING APPARATUS John E. P. Pickett, 3507 Ridge Road, Durham, N.C. 27705 Filed Feb. 15, 1965, Ser. No. 432,516 6 Claims. (Cl. 51-26) ABSTRACT OF THE DISCLOSURE A clinical type rotator is modified to receive a removable attachment such that the rotator when not being used by a laboratory technician for its normal purpose of shaking and mixing the contents of beakers and the like can be used for resurfacing microtome plates. When used for resurfacing microtome plates, the attachment enables the rotator platform to receive a pair of vertically stacked microtome plates each with a worn surface and with the worn surfaces opposed such that the worn surfaces act as abrading tools for each other and are both simultaneously resurfaced.

This invention is generally concerned with plate glass honing or dressing apparatus. More specifically, the invention is concerned with an apparatus for resurfacing glass hone plates of the kind employed to sharpen microtome knives.

Among histology technicians it is known that the quality of the tissue sections obtained and to some extent, the time required for preparing tissue sections depends on the sharpness and the evenness of the edge of the microtome cutting knife. The maintenance of sharp knives is therefore an important but time-consuming task in the modern tissue laboratory particularly when a sizeable number of microtomes are in constant use as in many of our major medical centers.

Microtome knife sharpening has essentially become an automated process with modern knife sharpeners which hold the knife and automatically slowly stroke the knife edge back and forth first on one side and then on the other against glass honing plates. For example the Automatic Microtome Knife Sharpener, Model 935 made by the American Optical Company of Buffalo, New York operates in this manner. The advent of the automatic knife sharpener has brought with it however the problem of having to periodically resurface the glass honing plate which is used in the automatic knife sharpener in order to re-establish a perfectly even surface. That is, after a certain number of knives have been honed and sharpened on a particular glass honing plate surface, that portion of the surface which has actually been stroked by the knife becomes worn so deeply that it must be resurfaced. Therefore, where a tissue laboratory is employing a large battery of microtomes it is faced with the alternative of either disposing of the relatively expensive glass honing plates which are used to sharpen the knives or else the laboratory must find some means to economically hone the worn glass honing plates so as to restore the evenness of their surfaces.

The task of resurfacing microtome knife sharpener glass honing plates has conventionally been accepted as a very time-consuming hand operation. For example, in many of the large tissue laboratories it is not uncommon to see several persons employed at the task of rubbing pairs of glass honing plates together in an orbital motion and with a grinding compound between the plates for the purpose of restoring the evenness of the honing surfaces used to sharpen the microtome knives.

With the foregoing in mind, an object of the present invention is to reduce the amount of time required to ICC microtome knife sharpener glass honing plates which can be incorporated as an attachment to a clinical rotator apparatus.

Another object is to provide an apparatus for resurfacing microtome knife sharpener glass honing plates which can be easily regulated in its speed of action so as to accommodate to fine and coarse honing requirements.

The foregoing and other objects of the invention will become apparent from the following description and the drawings, in which:

FIGURE 1 is an exploded perspective view of a microtome knife sharpener glass plate resurfacing apparatus enibodying the invention and illustrating how pairs of plates are placed for resurfacing.

FIGURE 2 is a plan view of the same apparatus and showing the position of the plates being resurfaced.

FIGURE 3 is a front elevation view of the apparatus.

FIGURE 4 is a side elevation view of the apparatus.

FIGURE 5 is a front elevation view illustrating an alternate plate holding means.

FIGURE 6 is a front elevation view illustrating an alternate mounting construction.

FIGURE 7 is a side elevation view illustrating a further alternate mounting construction.

FIGURE 8 is a perspective of a further alternate plate holding means.

Prior to describing the invention in reference to the drawings it may be noted that the invention is primarily directed to an attachment apparatus for a clinical rotator such that the rotator becomes available to serve as a means for resurfacing microtome knife sharpener glass honing plates. That is, with the attachment of the invention installed on the rotator, the rotator, in its conventional form, can be used as a means for resurfacing the glass honing plates without expenditure of manual labor. Since clinical rotators are normally available as standard equipment in tissue laboratories, the invention provides a simple attachment for converting the rotator to a honing plate resurfacing apparatus. Since rotators come equipped both with timing and speed control, the attachment of the invention lends itself to a resurfacing operation which can be automatically cut off at a certain time and which can be regulated to a particular speed depending on whether coarse or fine honing plates are being resurfaced, the amount of resurfacing required and the nature of the honing compound being used. Furthermore, the invention utilizes the inherent circular path of the clinical rotator platform and its frictional surface. The apparatus of the invention lends itself to simple installation and removal so that the rotator can still be used for its usual purposes when not required for resurfacing.

Referring to the drawings, there is illustrated a typical clinical rotator 10 having an on-off switch 11, an electrical power supply 12, a timer 13 and a speed control generally indicated at 14. For example, the drawings illustrate the Eberbach Clinical Rotator Type R-4l60, made by the Eberbach Corporation of Ann Arbor, Michigan. This particular rotator has a thirteen inch by thirteen inch platform, indicated at 20; a zero to thirty minute range in timer 13 and a wide speed variation in the speed control 14. The platform is conventionally covered with a the invention resides in the glass plate holders 22, 23 which may be secured to the sides 24, 25 of the rotator housing by means of screws 26. Alternatively, holders 22, 23 may be hinged to the sides 24, 25, as illustrated in FIGURE 6, by means of hinges 27 which are secured to the respective rotator sides and holders. A particular advantage of the hinged construction is that the plate holders 22, 23 may simply be folded away from the rotator platform as indicated by the dotted line positions 22, 23 in FIGURE 6. With the holders 22, 23 folded back to positions 22', 23' the whole of the rotator platform is freed for other purposes. As best illustrated in FIGURE 7, the holders 22, 23 may be provided with typical locking slots shown at 30, 31, having enlarged portions 32, 33 to accommodate the large heads of fixed studs and narrow slots 34, 35 to accommodate the stems, not shown, of the same studs. Such a detachable type construction is of course well understood in the art and provides a means by which the holders 22, 23 can be quickly and entirely removed from the rotator,

As best shown in FIGURE 1, the type of rotator illustrated accommodates a first pair of glass honing plates 40, 41 on one end of platform 20 and a second pair of honing plates 42, 43 on the opposite end of platform 20. On top of each pair of plates there is placed a pressure means for maintaining a fixed, uniform, pressure against the upper plates. In FIGURE 1, this is illustrated as comprising a pair of metal plates 45, 46, preferably of about two pounds weight each which rest on the uppermost plates 40, 42. Pressure plates 45, 46 are formed in the same shape as the glass honing plates and are preferably fitted with rubber bands 47, 48 which assist in keeping the pressure plates in position as the rotator rotates during resurfacing.

With regard to the means for maintaining a pressure on the upper plates, the previously mentioned metal pressure plates 45, 46 furnish a very simple means for this purpose. However, a pair of pivoted and spring loaded levers such as indicated at 50, 51 in FIGURE and employing springs 52, 53 and suitable pressure pads 54, 55 may be used to apply the needed pressure. As further shown in FIGURE 5, the levers 50, 51 may be supported by means of the uprights 56, 57 secured to the respective holders 22, 23 and may be raised to the dotted line positions 50, 51 when plates are being changed.

Positioning of the glass plates on the platform 20 is assisted by means of the guide lines 60, 61 which are painted on the surface of the sponge rubber covering sheet 21 and which show in outline where the bottom plate of each pair should be positioned.

Referring further to the details of holder plates 22, 23 it will be noted that holder 22 is provided with an outwardly turned U-shaped portion 70 and holder 23 with a similar U-shaped portion 71 the purpose of which is to give clearance for movement of the rotator platform 20. It will also be seen that holder 22 includes a cantilevered platform section 72 and holder 23 a similar cantilevered platform section 73. The respective sections reside above the platform covering sheet by a distance D, FIGURE 3, which is approximately equal to one and one-half times the normal thickness of the glass honing plate. That is, distance D should exceed the thickness of one plate but be less than the thickness of two plates. Each platform section contains a pair of notches such as indicated at 75, 76 for section 22 and at 77, 78 for section 23. Notch 75 is disposed exactly opposite notch 77 and notch 76 is disposed opposite notch 78.

In explaining use of the attachment apparatus of the invention, it is assumed that plates 40, 41, 42 and 43 represent worn plates having uneven surfaces in need of resurfacing. Accordingly, in use plate 41 is positioned within the guide line 60 and with a worn surface turned up. Plate 41 is thus free to rotate with the rotator plat form beneath the overlying edges of sections 72, 73 of the holders 22, 23. Plate 40 is placed on top of plate 41 with the ends of plate 41 engaging the respective notches 75, 77 such that plate 41 is restrained from movement. Pressure plate 45 is next placed on top of plate 40. In a similar way, glass plate 43 is placed within guide line 61, glass plate 42 is placed on top of glass plate 43, and pressure plate 46 is placed on top of glass plate 42. Glass plate 43 is thus free to rotate with the rotator platform 20 in the same way as glass plate 41 while the ends of glass plate 42 are being restrained in notches 76, 78.

Prior to assembly of the glass honing plates and pressure as previously discussed, it should be understood that a suitable grinding paste is applied to those surfaces of the glass plate which are being rubbed together. While the practice of histology technicians will vary it has been found that a suitable grinding paste can be made from one part Hone Glass Compound (American Optical Company, Buffalo, New York) and four parts water. Eight to ten drops of such a mixture, well shaken, should be placed on the lower glass plates 41, 43.

After assembly of the honing and pressure plates with the grinding paste, the timer is set according to the time deemed to be required and switch 11 is turned on to start rotary movement of platform 20. Two to three fiveminute periods with the grinding paste being restored between each period is generally sufiicient to restore the surfaces. As platform 20 rotates, plates 40 and 42 will be held stationary in the holders 22, 23 while plates 41, 43 will rotate with platform 20. As further evidence of the simplicity of the invention, it has been found that once plates 41 and 43 are positioned within the respective guide lines 60, 61 they will generally maintain such positions due to the inherent frictional surface of the sponge rubber covering sheet 21. That is, experience has shown that no special holding means is required to keep plates 41 and 43 in position. At the same time the pressure plates 45, 46 maintain contact between the surfaces being ground which assures a constant grinding action. Of course, as previously mentioned, the desired pressure may be applied by other means such as the pivoted spring loaded lever arrangement previously discussed in connection with FIGURE 5.

While the upper plates are held stationary so far as horizontal movement is concerned, it should, of course, be understood that the upper plates are free to slide vertically Within the notches as the abrading action takes place and wears away material. Furthermore, it should be recognized that the operator will normally place worn surfaces of both the upper and lower plates in contact and will thus use the resurfacing apparatus to resurface two surfaces at the same time on each pair of plates. The example chosen has illustrated two pairs of plates being resurfaced but it will be apparent that the invention adapts itself to abrading less than two or more than two pairs simultaneously.

In FIGURE 8, the invention assumes the form of a bent integral panel structure into which the rotator can be placed and which includes as part of the structure the previously described types of holders. In FIGURE 8 the length L and width W of the bottom panel member 80 are made to correspond to the length and width of the bottom of rotator housing so that the rotator can rest and be supported on member 80. Extending upwardly from bottom panel member 89 are two side panels 81, 82 of height H corresponding to the height of the sides of the rotator housing. In use, the rotator will of course rest between side panels 81, 82 and the U-shaped end portions 83, 84 will extend around and clear the platform edges for movement. The notched top panels 85, 86 correspond to the previously discussed panels 22, 23 and serve the same purpose. Weights such as weights 45, 46 may be employed with the structure of FIGURE 8 or other pressure devices may be used. In any event, it can be seen that the particular advantage of the FIGURE 8 structure is that the clinical rotator can simply he slipped into position in the FIGURE 8 type structure and be immediately adapted to perform microtome knife sharpening' plate resurfacing.

Having described the invention, what is claimed is:

1. An apparatus for simultaneously resurfacing a worn surface on each of a pair of microtome plates by using the worn surface of each as an abrading tool for the other comprising:

(a) a clinical rotator having a housing, a frictionally surfaced rotatable platform supported above the housing, said platform being adapted to frictionally position and rotate a first one of a pair of worn microtome plates, and means within the housing for rotating said platform;

(b) a holder secured to said housing and overlying said platform above and free of contact with said first plate and extending from said housing outside the swing of the edges of said platform, said holder being adapted to removably engage the edges of the second one of said pair of plates and maintain said second plate superposed upon said first plate so that respective worn surfaces of each are in opposed engagement, said second plate being restrained by said holder from horizontal movement while being free to move vertically;

(0) means for applying a constant uniform pressure to the exposed surface of said second plate to maintain uniform contact between said first and second plates; and

(d) an abrasive mixture coating the worn and contiguous surfaces of said first and second plates whereby upon the movement of said platform, said first plate moves relative said second plate and, in combination with said abrasive mixture, simultaneously causes the contiguous surfaces of said plates to become fiat and smooth.

2. An apparatus as claimed in claim 1 wherein said holder comprises a pair of notched panels secured to said sides of said housing and the contour of the notches therein mate with the contour of said edges.

3. An apparatus as claimed in claim 2 wherein said panels are hingedly secured to said sides.

4. An apparatus as claimed in claim 2 wherein said panels are removably secured to said sides,

5. An apparatus as claimed in claim 1 wherein said holder is adapted to removably engage the upper of two pairs of said plates.

6. An apparatus for simultaneously resurfacing a worn surface on each of a pair of microtome plates by using the worn surface of each as an abrading tool for the other comprising:

(a) a clinical rotator having a housing, a frictionally surfaced rotatable platform supported above the housing, said platform being adapted to frictionally position and rotate a first one of a pair of worn microtome plates, and means within said housing for rotating said platform;

(b) an integral shaped panel structure detachably secured to said clinical rotator and including a bottom panel for supporting said housing, a pair of oppositely and vertically disposed side panels for receiving said housing therebetween and a pair of oppositely and horizontally disposed top panels overlying said platform above and free of contact with said first plate and supported from said side panels outside the swing of the edges of said platform, said top panels having notched portions in the edges thereof adapted to removably engage the edges of the second one of said pair of plates and maintain said second plate superposed upon said first plate so that respective worn surfaces of each are in opposed engagement, said second plate being restrained by said notched portions from horizontal movement while being free to move vertically;

(c) means for applying a constant uniform pressure to the exposed surface of said second plate to maintain uniform contact between said first and second plates; and

(d) an abrasive mixture coating the worn and contiguous surfaces of said first and second plates, said abrasive mixture causing frictional and abrasive contact between said plates but which is less than the frictional contact between said first plate and said platform whereby said first plate rotates with said platform and relative to said second plate and, in combination with said abrasive mixture, simultaneously causes the contiguous surfaces of said plates to become flat and smooth.

References Cited UNITED STATES PATENTS 783,086 2/1905 Stewart 51-216 X 863,190 8/1907 Le Blanc -26 1,420,751 6/ 1922 Ricketts 51-26 1,872,416 8/1932 Crowley 51-26 1,995,676 3/1935 Gagnon 51-1l1 2,362,501 11/1944 Salabes 51216 ROBERT C. RIORDON, Primary Examiner. J. A. MATHEWS, Assistant Examiner. 

1. AN APPARATUS FOR SIMULTANEOUSLY RESURFACING A WORN SURFACE ON EACH OF A PAIR OF MICROTOME PLATES BY USING THE WORN SURFACE OF EACH AS AN ABRADING TOOL FOR THE OTHER COMPRISING: (A) A CLINICAL ROTATOR HAVING A HOUSING, A FRICTIONALLY SURFACED ROTATABLE PLATFORM SUPPORTED ABOVE THE HOUSING, SAID PLATFORM BEING ADAPTED TO FRICTIONALLY POSITION AND ROTATE A FIRST ONE OF A PAIR OF WORN MICROTOME PLATES, AND MEANS WITHIN THE HOUSING FOR ROTATING SAID PLATFORM; (B) A HOLDER SECURED TO SAID HOUSING AND OVERLYING SAID PLATFORM ABOVE AND FREE OF CONTACT WITH SAID FIRST PLATE AND EXTENDING FROM SAID HOUSING OUTSIDE THE SWING OF THE EDGES OF SAID PLATFORM, SAID HOLDER BEING ADAPTED TO REMOVABLY ENGAGE THE EDGES OF THE SECOND ONE OF SAID PAIR OF PLATES AND MAINTAIN SAID SECOND PLATE SUPERPOSED UPON SAID FIRST PLATE SO THAT RESPECTIVE WORN SURFACES OF EACH ARE IN OPPOSED ENGAGEMENT, SAID SECOND PLATE BEING RESTRAINED BY SAID HOLDER FROM HORIZONTAL MOVEMENT WHILE BEING FREE TO MOVE VERTICALLY; (C) MEANS FOR APPLYING A CONSTANT UNIFORM PRESSURE TO THE EXPOSED SURFACE OF SAID SECOND PLATE TO MAINTAIN UNIFORM CONTACT BETWEEN SAID FIRST AND SECOND PLATES; AND (D) AN ABRASIVE MIXTURE COATING THE WORN AND CONTIGUOUS SURFACES OF SAID FIRST AND SECOND PLATES WHEREBY UPON THE MOVEMENT OF SAID PLATFORM, SAID FIRST PLATE MOVES RELATIVE SAID SECOND PLATE AND, IN COMBINATION WITH SAID ABRASIVE MIXTURE, SIMULTANEOUSLY CAUSES THE CONTIGUOUS SURFACES OF SAID PLATES TO BECOME FLAT AND SMOOTH. 